Description
Full-Range ERW Hollow Section Supply — Q195 through Q345 square and rectangular tubes in 300×300mm and custom sizes, stocked and processed under one roof with ASTM and EN standard compliance.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 ERW Square and Rectangular Steel Tube |
| Product Type | ERW Welded Square and Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Square / Rectangular |
| Size Range | 300×300mm and other sizes per request |
| Length | 6m standard, customizable |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Ends | Plain (default) |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Structure Pipe, Fluid Pipe, Boiler Pipe, Oil Pipe, Gas Pipe, Chemical Fertilizer Pipe, Drill Pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, column supports, bridge handrails, scaffolding structures |
| Machinery Manufacturing | Equipment base frames, conveyor supports, crane boom sections |
| Oil & Gas | Gas distribution lines, fuel transfer pipes, drill pipe casings |
| Petrochemical & Fertilizer | Boiler tubes, heat exchanger supports, chemical fertilizer pipeline systems |
| Steel Fabrication | Warehouse portal frames, mezzanine structures, heavy-duty rack systems |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on ERW square and rectangular tubes is the difference between passing site inspection and scrapping an entire batch.
Structural hollow sections are specified by engineers based on calculated load-bearing capacity tied to exact wall dimensions. When actual thickness drifts beyond tolerance — especially with negative tolerance practices common in spot-market supply — the section modulus drops, weld fit-up fails, and load tests come back short. Buyers sourcing ERW square and rectangular steel tube ASTM standard compliant products from fragmented suppliers often discover tolerance gaps only after cutting has begun, turning a material cost problem into a project delay crisis. [NEED_CITE: EN 10219 dimensional tolerance requirements for cold-formed hollow sections]
How Q235 and Q345 Hollow Sections Match Structural Load Requirements
Q235 serves general structural frames where moderate load capacity suffices — warehouse columns, light industrial buildings, and non-critical support structures. Q345 steps into higher-stress applications: crane runways, heavy equipment bases, and bridge components where yield strength directly governs section selection. The ERW welding process produces a continuous longitudinal seam with consistent geometry across the full 300×300mm profile, and the ±1% tolerance ensures that fabrication drawings translate directly to fit-up on site. Our in-house cutting and punching services mean that 6m lengths arrive pre-processed to exact project dimensions, eliminating secondary work at the fabrication shop.
Engineering Compliance and Certification Pathways
Structural hollow sections used in load-bearing frames must conform to recognized engineering codes — AISC for North American projects, EN 1993 for European designs, and local building codes across Southeast Asia and the Middle East. The ASTM A213 and DIN EN 10217-1 standards referenced in our specifications provide the material testing and chemical composition framework that engineers require for design approval. For projects requiring third-party verification, SGS and BV inspection reports are arranged against the original heat number, ensuring that every ERW square and rectangular steel tube ASTM standard shipment carries full traceability from coil to finished section. [NEED_CITE: steel grade equivalence mapping between GB Q-series and ASTM A500]
Understanding ERW Welding, Steel Grade Selection, and Surface Protection
The ERW process passes high-frequency current through the strip edges, fusing them under pressure without filler metal — producing a weld seam that matches base metal strength when properly controlled. Q195 and Q215 offer formability for bending and punching operations, while Q235 and Q345 deliver the yield strength progression that structural engineers specify for increasing load tiers. The hot-rolled surface with slight oiling provides transit corrosion protection without interfering with subsequent galvanizing or painting. Wall thickness tolerance at ±1% means the theoretical weight calculation used in procurement budgets aligns with actual delivered weight — a detail that matters when orders run into hundreds of tons.
The Hidden Cost of Unverified Hollow Section Procurement
Material substitution without documentation creates compounding liabilities: a Q235 section delivered as Q345 passes visual inspection but fails load testing; a wall thickness running negative by even a fraction of a millimeter reduces section modulus below design assumptions; missing mill test certificates block customs clearance in markets requiring EN or ASTM certification. [NEED_CITE: consequences of missing mill test certificates in steel import customs clearance] These failures surface not at the mill gate but at the project site — during welding inspection, during structural load testing, or during final handover documentation — when rework costs dwarf the original material savings from unverified sourcing.
Why Engineering Procurement Teams Source ERW Square and Rectangular Steel Tube ASTM Standard Products Through Us
Our Shandong production base sits within the densest cluster of square and rectangular tube mills in northern China, giving us direct access to rolling schedules and finished stock across the full Q195–Q345 range. Every shipment carries an original mill test certificate documenting chemical composition and mechanical properties by heat number — not a template document generated after the fact. Our in-house processing facility handles cutting to length, punching, and bending against project drawings, so fabricators receive components ready for assembly rather than raw lengths requiring secondary work. Professional heavy cargo loading experience means that 6m tubes are secured with proper edge protection and weight distribution, avoiding container damage and overweight penalties that plague inexperienced shippers. ISO 9001:2015 certification and CE marking provide the compliance framework that engineering consultants and project owners require for vendor approval.
Documentation & Compliance
- Mill test certificate documenting Q235 or Q345 chemical composition and mechanical properties per ASTM A213 or DIN EN 10217-1, linked to original heat number
- CE certificate confirming compliance with EN 10217-1 for pressure and structural applications in European markets
- ISO 9001:2015 quality management certificate covering the full production and inspection process for ERW welded hollow sections
- SGS or BV third-party inspection report available upon request, verifying dimensional tolerance, surface condition, and weld seam quality before shipment
- Full material traceability from raw material coil through ERW forming to finished square and rectangular section, with heat number marked on each piece
- Export documentation including packing list, bill of lading, and certificate of origin formatted for destination-country customs requirements
Packaging, Loading & Delivery
- ERW square and rectangular tubes bundled with high-tensile steel strips at intervals sized to prevent shifting during ocean transit, with edge protectors preserving the slightly oiled hot-rolled surface
- 6m standard lengths loaded in 20ft and 40ft containers with weight distributed across axles to avoid overweight penalties; custom-cut lengths packed separately and marked by project reference
- Surface protection maintained through slight oiling applied after final inspection, preventing rust formation during humid coastal shipping without interfering with downstream galvanizing or painting
- Heat number, steel grade (Q235 or Q345), and dimensional specifications stenciled on each bundle for site identification and inspection traceability
- FOB, CIF, and DDP shipping terms available; professional flatbed and open-top container loading for oversized sections exceeding standard container dimensions
- Typical production lead times apply for standard specifications; custom-cut and processed orders confirmed against current mill rolling schedules at inquiry stage
Starting Your ERW Hollow Section Procurement
Submit your specification sheet — steel grade, section dimensions, wall thickness, length, quantity, and destination port — and receive a detailed quotation including material cost, processing fees, and shipping terms within twelve hours. We provide the original mill test certificate for your quality verification before shipment, and our processing team confirms cutting and punching details against your fabrication drawings before production begins.
Request Quotation with Mill Test Certificate
Send your ERW square and rectangular steel tube ASTM standard requirements to our technical team for specification matching, pricing, and certification confirmation.
Company: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjyplate.com
Website: www.xjyplate.com
Frequently Asked Questions
Q: How do Q235 and Q345 grades compare to ASTM A500 and EN 10219 standards?
A: Q235 and Q345 are Chinese national standard grades with chemical composition and mechanical property ranges that map to ASTM A500 Grade B and EN 10219 S235/S355 respectively. We provide equivalence documentation for engineering approval, and our mill test certificates report actual test values against the specified standard so your design team can verify compliance directly.
Q: Can you provide third-party inspection and original mill test certificates?
A: Yes. Every shipment includes an original mill test certificate documenting chemical composition and mechanical properties by heat number. SGS and BV third-party inspection reports are arranged before shipment upon request, covering dimensional verification, surface condition, and weld seam quality.
Q: What is the MOQ for custom-cut square and rectangular tubes?
A: The standard MOQ is 5 tons. For custom-cut lengths, punching, or bending processing, we confirm minimum quantities against your specific drawing requirements at the inquiry stage, as setup considerations vary by profile size and processing complexity.
Q: What surface treatment options are available for ERW hollow sections?
A: Standard supply is hot-rolled with slight oiling for transit protection. Additional surface treatments including hot-dip galvanizing, painting, or specialized coatings can be arranged as secondary processing based on your project specifications and environmental requirements.
Q: How do you handle container loading for long-length structural tubes?
A: Our loading team has extensive experience with heavy cargo and long-length steel products. Six-meter standard lengths are weight-distributed across container axles to avoid overweight penalties, and custom lengths are packed with edge protection to preserve surface condition. For sections exceeding container dimensions, open-top or flatbed loading is arranged.
